


The science checks out

by notallballs (notallbees)



Category: Haikyuu!!
Genre: Alternate Universe - Modern Setting, Alternate Universe - Science Fiction, Dendrophilia, Dubious Consent, Dubious Consentacles, Dubious Science, For Science!, M/M, Magical Realism, Other, Plants, Restraints, Sex Pollen, Sleep Groping, Sleep Sex, Somnophilia, Tentacle Sex, Tentacles, Wet Dream, Xenophilia
Language: English
Status: In-Progress
Published: 2019-01-04
Updated: 2019-01-04
Packaged: 2019-10-04 06:35:47
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,020
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17299595
Author URL: https://archiveofourown.org/users/notallbees/pseuds/notallballs
Summary: Tooru's knack with plants was rather uncanny sometimes, but this strange little sample had outdone them all.He'd called it Iwa-chan because of its strange shape at first, like a small figure hunched over, and because of the way the colour reminded him of damp rock, of moss and lichen on old stone steps.As he stepped into the bedroom, Iwa canted toward him slightly, and Tooru frowned. It was one of the strange behaviours he'd noted even when he first brought the plant home. Tooru tried hard not to anthropomorphise his samples, but there was something reminiscent of sentience in the way that Iwa seemed drawn to him like a source of light or heat.As a professor of botany, Oikawa has encountered all sorts of strange plants in his career, but none quite as strange as the mysterious sample he calls Iwa-chan. What starts as idle curiosity soon strays into uncharted territory as Iwa begins to take on more and more human qualities, and the lines between scientific and sexual discovery become inextricably blurred.





	The science checks out

**Author's Note:**

  * For [pussycat_scribbles](https://archiveofourown.org/users/pussycat_scribbles/gifts).



> it's here at last, or at least some of it - my grand iwaoi plantfucking epic. alternatively titled 'oikawa licks things for science'. thank you to all of you for being so patient, and especially to em who has been more patient than anyone ♥ happy birthday em! also please have a moment of silence for me trying to tag this fucking thing.
> 
> please also check out the fanart that pussycat did for these a million years ago - [here](https://notallballs.tumblr.com/post/153619759877/pussycat-scribbles-okay-but-what-if) and [here!](https://notallballs.tumblr.com/post/154138608967/pussycat-sins-so-if-you-follow-my-main-blog-you)
> 
>    
>  **Warnings:** see end notes for warnings!

Tooru had never liked Thursdays. He had a full day of classes on Thursdays, and on top of that they always had a faculty meeting on Thursday mornings. He was feeling rather worse for wear when he dragged himself into work that particular Thursday morning, and that was before he rolled up fifteen minutes late for the meeting and had to endure his colleagues teasing him for his tardiness.

"You look like something that just crawled out of the sewer," Kuroo murmured as Tooru collapsed into the seat beside him. "Bad night?"

Tooru shook himself and straightened up, wishing he'd taken the extra couple of minutes to buy himself a coffee on the way in. "Something like that."

Kuroo hummed softly. "You sure you're okay? This has been going on for a while."

Tooru shrugged. 

"You're putting way too much time into that new project—" 

"Kuroo-kun," the head of department said mildly. "Do you and Oikawa-kun have something to share with the rest of the faculty?" 

Tooru snorted, and Kuroo raised his head with an unapologetic smile. "Sorry about that, Irihata-sensei!" 

Clearing his throat, Irihata continued, and Tooru let himself sink back in his seat while the older man's words washed over him. Kuroo wasn't wrong; for the past two weeks, Tooru had woken up every morning feeling as though he'd barely slept. He'd tried going to bed earlier, or exercising before he slept, but nothing seemed to make a difference. And then there were the dreams he'd been having; wildly vivid, full of colour and scent, most of them intensely erotic. Tooru had woken up with sticky sheets most mornings, something he hadn't even experienced during the most frenetic periods of puberty.

The faint shades of a dream from that morning came back to him; he was in a thick glade, verdant foliage and heavy blooming flowers all around him, their sweet, musky scent almost overpowering. Tooru was submerged in a pool of water up to his collarbone, and beneath the dark water something manipulated him slowly, unseen hands stroking him and teasing at his entrance. 

"Oikawa-sensei?"

Tooru blinked awake to find that the meeting was over, and most of his colleagues had already left. A small hand touched his wrist. 

"Oikawa-sensei, are you alright?" 

Tooru looked up to find Yachi leaning over him. "Yacchan," he said, a tired smile pulling across his face. "Sorry, I was miles away." 

"You certainly were," she said, returning his smile shyly. "Is everything okay?" 

He nodded, gathering up his things. "Damn—what time is it?" 

"Almost nine," she said, glancing at her watch. 

Tooru swore. "Sorry, Yacchan, I'm late for class. Let's catch up later!" 

"Oh, alright." 

There still wasn't time to stop for coffee, but Tooru did so anyway, dipping into the canteen on his way to the lecture theatre. His first lecture of the day was with his final year students, so he needed to be awake for it, and not dwelling on his perverted dreams. 

Teaching, at least, was somewhere he felt comfortable and in control, and he made it through his morning classes without incident. Two of his first years stopped him on the way out of his final class to ask him whether he was alright, but he shrugged them off easily and went to hide in his office. 

It was Yahaba who found him first, waking him with a gentle hand on his shoulder. Tooru hadn't even been aware he'd been asleep, but sure enough his hands were numb and his neck ached from sleeping on his folded arms on his desk. He straightened up, wincing and trying to suppress a yawn. 

"Are you alright, Oikawa-sensei?" 

"Yahaba," he murmured, rubbing his cheek where his glasses had dug into his face. "Sorry, did you need me for something?" 

"You wanted to go over those results today?" Yahaba prompted. "From the samples you took?" 

Tooru winced. "Right, yes, sorry." He glanced around for his phone. "What time is it?" 

"A little after one." 

"Good," Tooru said, nodding. He still had a good thirty minutes before he needed to head to his next class. He gestured for Yahaba to sit. "Do we still have any of that dark roast left?" 

Yahaba grimaced. "Uh—" 

"Never mind," Tooru said, shaking his head. "What did you find?"

"Nothing that unusual," Yahaba said, lifting up a folder as he took his seat. "Nothing to really explain why it grows so fast, or the rapid morphological changes."

"Curious," Tooru murmured, holding his hand out for the file. "And you still don't know where it came from?" 

Yahaba shook his head. "Sorry, Oikawa-sensei. Somehow it slipped through the net, there are no records at all of when we received the sample, or where it came from." 

Tooru frowned as he glanced over the report. It had been a month since the strange sample turned up in his office, and after some initial tests had shown it to be relatively harmless, Tooru had taken it home with him to see if he could get it to flourish. Flourish it had; Tooru had always had a particularly green thumb, but even he was surprised by the way the plant had transformed from an awkward, spiny little grey stump, to a trailing, waist-high plant with short, bushy leaves and some rather curious-looking runners. He'd been documenting the plant's development with endless notes and photographs, but had been hesitant to take any cuttings before he knew more about it, not wanting to risk stunting its incredible growth.

"There is one interesting thing," Yahaba continued, gesturing for Tooru to turn the page. "It has a compound—I assume it secretes it—that would make for a powerful sedative. Better be careful about touching it."

Tooru laughed. "I don't know, maybe I could do with some of that," he murmured, thinking back to his disturbed night. "But don't worry, Yahaba-chan, I can see that little crease forming already. No need to give yourself wrinkles on my account, I'll be careful."

"Thank you, Oikawa-sensei. There's no evidence that the plant is harmful, but best to be careful."

"Yes indeed." He sighed, sitting back in his chair, and reached up to rub his tired eyes behind his glasses. 

Yahaba stood up. "I'll see if Kuroo-sensei has any coffee going spare."

Tooru groaned. "Yahaba-chan, you're an _angel_."

"I don't know about that," Yahaba said, grinning. "But thanks. Shall we look at it again next week? Maybe you could bring in another sample, we could try propagating it here in the lab."

"Mm, why not," Tooru murmured, running his eyes over the report again. "Couldn't hurt to try."

 

—

 

Tooru had always been a sucker for a good mystery. 

It was part of the reason he pursued science. Tooru loved mysteries, and the best way he knew how to solve a mystery was to break it down into its component parts. That's what he loved most about science.

He fell into botany sort of by accident. He didn't have the skill in maths to study astrophysics, but while studying his biology undergrad he went to a guest lecture about paleobotany that talked about the links between fossilized samples, and the likelihood of finding evidence of plant life elsewhere in the solar system. Tooru had gone home bubbling with excitement, and the next day had filled the windowsill of his bedroom with plants from the florist down the street.

Most of those plants still graced the windowsill of his office at the university, while his apartment was a riot of colour and leafy chaos, overflowing with samples, cuttings and house plants he'd picked up or received as gifts. His mother had a habit of buying him finicky orchids, sourcing the rarest breeds and hybrids she could find. In his darker moments, Tooru was convinced that she was trying to test him; he didn't even particularly like orchids, and they were notoriously difficult to keep, but his green thumb had yet to fail him. He even ran an unofficial hospital for friends with ailing houseplants; a few days with Tooru nearly always saw them blooming again, rising like lazarus from wilt or neglect. 

His knack with plants was rather uncanny sometimes, but this strange little sample had outdone them all. 

"Iwa-ch—an!" Tooru called out as he arrived home that evening. "I'm b—ack!" 

An inevitable silence followed his words, and Tooru grinned, reassured by the peace and quiet. His office wasn't exactly _hectic_ , but there were always people around, whether it was Kuroo and Yachi, or Tooru's own students and associate lecturers coming and going. Here, he was truly alone, in the best sense of the word.

He made himself some tea, and then went into his bedroom to change and check on the plant. He'd called it Iwa-chan because of its strange shape at first, like a small figure hunched over, and because of the way the colour reminded him of damp rock, of moss and lichen on old stone steps. He'd kept Iwa-chan in a makeshift quarantine chamber at first, something he always did when bringing home a new plant, but Iwa had outgrown it within days, and so Tooru had moved it to his bedroom instead, shifting the few existing residents out to the living room. Plants nearly outnumbered books in his apartment, and every horizontal surface was crowded with pots. Tooru dreaded ever having to move house. 

As he stepped into the bedroom, Iwa canted toward him slightly, and Tooru frowned. It was one of the strange behaviours he'd noted even when he first brought the plant home. Tooru tried hard not to anthropomorphise his samples, but there was something reminiscent of sentience in the way that Iwa seemed drawn to him like a source of light or heat. Perhaps, to Iwa, he really was a source of food; he'd cut himself more than once on Iwa's razor-sharp spines after first bringing him back, and he couldn't help noticing that Iwa's rapid growth had only started after that. Tooru hummed to himself as he stripped off his work clothes, pondering the reception of a paper discussing the plant's apparent vampire-like qualities. He'd been more careful since then to avoid touching Iwa's spines, but the plant's rapid growth hadn't abated. In fact, it had only grown more intense. 

"You certainly are a mystery," Tooru murmured to himself, going over to his bed and flopping down on his stomach. Iwa was propped on a box at the end of his bed, and Tooru cradled his face in his hands as he looked over the plant intently, searching for some kind of answer in the strange shape of its leaves, the intriguing curl of its slender runners. He breathed out heavily. "What on earth are you?"

As he watched, Iwa leaned toward him again, as though stirred by the heat of his breath. One thin runner uncurled slowly, extending out toward him slowly. 

Tooru sat up, blinking in surprise. "What," he murmured, staring at the runner slowly reaching toward him. " _What_?" He turned, scrambling for his phone. "That's not—this isn't _possible_ , Iwa-chan," he said, laughing as he fumbled with the screen, trying to start it recording. But just as he finally got it recording, Iwa shuddered to a halt and stopped, tendril extended but unmoving. 

Tooru pouted at the plant. "Aw, Iwa-chan," he sighed. "Spoilsport." He checked the time, then did his daily checks and measurements of Iwa, before going about his daily watering routine. 

When he was done, he ate some leftover soup before crawling back into bed to mark assignments, his phone at his side and one eye on the plant by his feet in case it decided to try something again. He made it through about half his assignments before he simply fell asleep, notes crumpled all around him.

 

—

 

It was dark when Tooru blinked awake. His limbs were strangely heavy, and he felt almost suffocated by the heat suffusing him; sweat ran down the side of his face and his limbs stuck to the sheets. With a great deal of effort, he lifted one hand slowly and pressed it against his cock, groaning softly at the faint relief it brought. He was painfully hard. He couldn't remember feeling this turned on before, and he tried to lift his knees so he could remove his underwear, only to find that he couldn't move his feet. 

Tooru's heart thudded in his chest. He scrambled to turn on the light beside his bed and craned his neck to look down at his feet. It took him a moment to make sense of what he was seeing. Thick tendrils sprouted out of Iwa's pot and curled around his ankles, securing him in place, while more of his runners trailed up Tooru's legs and disappeared under the hem of his underwear. As Tooru stared, dumbstruck, one of the tendrils shifted in his underwear and a terrific, spine-tingling pressure squeezed around his cock.

"What the _fuck_ ," Tooru screeched, sitting bolt upright. He grabbed the waistband of his underwear and tugged it away from his skin; sure enough, one of Iwa's runners was wound around his cock like a leafstalk on a climbing plant, and as he watched it gave him a determined squeeze. Tooru stared. "What the fuck," he whispered. 

He reached down and tried—as delicately as he could—to unwind the tendril from around his cock. The tendril was pliable, allowing him to remove it, and then curling around his finger as he lifted it away. Tooru frowned and pushed it off, carefully pulling the errant tendrils out of his underwear while doing his best not to break off any of the small, greyish leaves. When they were free, the tendrils hovered for a moment before slinking back toward the pot, along with the ones that had been restraining his ankles. Tooru squinted at it; he could have sworn that the plant was more hunched over than usual, almost as though it was sulking or sheepish. 

_Stop assigning human qualities to a plant, you absolute lunatic,_ be told himself sternly, but it was difficult to rein in his racing thoughts after what he'd just witnessed. 

Normal function was starting to return to his heavy limbs, and Tooru shimmied up toward the head of the bed. He fumbled for his phone, not taking his eyes off Iwa, and turned on the voice recorder. 

"March 8th," he said breathlessly, running his fingers through his sweaty hair. "One fourteen AM. Woken in the night by nocturnal stirrings from the sample—" 

Iwa rustled suddenly, a slight shivering of his foliage that gave Tooru the strange impression of annoyance.

"—which showed possible signs of…interest? Awareness?" Tooru groaned and covered his face with his free hand. "Woke in a state of arousal to find myself being…stimulated by the sample, apparently using its runners as…tools." He paused, chewing his bottom lip thoughtfully. "Ask Yahaba to check whether the sample is capable of secreting an aphrodisiac in addition to—" Tooru broke off, eyes widening. "To a sedative," he murmured. 

Could it be possible? Was this the reason for his tiredness? If this wasn't the first time Iwa had… _explored_ , then it was possible he'd been using his sedative secretions to keep Tooru placid while he did so. 

"Moving the sample to another room until we've ascertained that it's safe," Tooru said, watching it carefully for any sign of a reaction. There was none, of course, and he felt silly for expecting one. 

Putting down his phone, he pulled on a hoodie, stretching the sleeves down over his hands. Thus protected, he heaved Iwa's pot in his arms, grunting at the weight, and walked it out to the other room. He wasn't sure how far Iwa-chan's tendrils could reach, and it seemed unlikely they possessed the strength to open a door, but it also seemed unlikely that a plant could grope him in his sleep, so it didn't feel absurd to take the precaution. Regardless, he felt better after he'd closed the door between him and Iwa. 

He washed his hands thoroughly, and then after a moment's hesitation got into the shower and scrubbed himself down, just in case. Running a bar of soap over himself, it was hard to ignore the fact that he was still aroused, his skin shivery, his cock heavy between his legs. As he started to touch himself, he wondered again just what Iwa had been trying to do. If he was going to go ahead and assign intent to a plant—was it threatening, or was it social? Was there something about Tooru that Iwa-chan craved, and would that go some way toward explaining why the plant always leaned toward him when he entered the room? 

Dismissing the useless speculations, Tooru groaned and tipped his head back against the wall, stroking himself harder. It was, he realised, weeks since he'd felt the need to touch himself this way—that, more than anything, went a long way to convincing him of Iwa-chan's nightly activities. He was aware that he ought to feel violated somehow, but all he felt was curiosity, and an overwhelming need to release the pressure that had apparently built up while he slept. Removed from the active danger of being manipulated against his knowledge, the thought of being restrained in that way held some appeal. Tooru gritted his teeth. How many people could say they'd been jerked off by a plant? He groaned and fisted his cock more tightly, letting himself luxuriate in the fantasy for a moment, in thoughts of being held down, being taken, helpless to resist. He shuddered as he came, spilling over his wrist and shooting halfway up his chest, something he thought he'd gotten too old to manage. 

After, he stuck out a hand to prop himself against the shower wall, weak and dizzied by the intensity of his orgasm. It was the hardest he'd come for a while. Tooru bit his lip as he ducked under the shower head and rinsed himself off. There was so much to explore here, he was rather excited to get started.

**Author's Note:**

> [RT on twitter](https://twitter.com/notallbees/status/1081292587489742850) | [my iwaoi fic](https://archiveofourown.org/works?utf8=%E2%9C%93&commit=Sort+and+Filter&work_search%5Bsort_column%5D=revised_at&include_work_search%5Brelationship_ids%5D%5B%5D=1329922&work_search%5Bother_tag_names%5D=&work_search%5Bexcluded_tag_names%5D=&work_search%5Bcrossover%5D=&work_search%5Bcomplete%5D=&work_search%5Bwords_from%5D=&work_search%5Bwords_to%5D=&work_search%5Bdate_from%5D=&work_search%5Bdate_to%5D=&work_search%5Bquery%5D=&work_search%5Blanguage_id%5D=&fandom_id=758208&user_id=notallbees)
> 
>    
>  **Warning:** Oikawa wakes in the night to find that Iwa has been groping him without his consent. He's not upset by this and doesn't really consider it a violation but it does initially happen multiple times without his knowledge.


End file.
